Scent-marking Sites Research Articles

Characterizing the metabolome and microbiome at giant panda scent marking sites during the mating season

Scent marking sites served as a primary means of chemical communication for giant pandas, enabling intraspecific communication. We integrated metabolomics and high-throughput sequencing techniques to examine the non-targeted metabolome and microbial community structure of scent marking sites and feces in the field. Integrative analysis revealed a more comprehensive array of chemical compounds compared to previous investigations, including ketones, acids, heterocycles, alcohols, and aldehydes. Notably, specific compounds such as 2-decenal, (E)-, octanal, decanal, L-α-terpineol, vanillin, and nonanal emerged as potential key players in scent signaling. Intriguingly, our study of the microbial domain identified dominant bacterial species from the Actinobacteria, Bacteroidetes, and Proteobacteria phyla, likely orchestrating metabolic processes at scent marking sites. Comparative analyses showed, for the first time, that feces do not share the same functions as scent markers, indicating distinct functional roles. This research deepens scientific understanding of chemical communication in wild pandas.

Effects of snow leopards (Panthera uncia) on olfactory communication of Pallas’s cats (Otocolobus manul) in the Altai Mountains, Mongolia

Abstract Olfactory communication is important for many solitary carnivores to delineate territories and communicate with potential mates and competitors. Pallas’s cats (Otocolobus manul) are small felids with little published research on their ecology and behaviour, including if they avoid or change behaviours due to dominant carnivores. We studied their olfactory communication and visitation at scent-marking sites using camera traps in two study areas in Mongolia. We documented four types of olfactory communication behaviours, and olfaction (sniffing) was the most frequent. Pallas’s cats used olfactory communication most frequently at sites that were not visited by snow leopards (Panthera uncia) and when they used communal scent-marking sites, they were more likely to use olfactory communication when a longer time had elapsed since the last visit by a snow leopard. This suggests that Pallas’s cats may reduce advertising their presence in response to occurrence of snow leopards, possibly to limit predation risk.

Using heterogeneous camera-trapping sites to obtain the first density estimates for the transboundary Eurasian lynx (Lynx lynx) population in the Dinaric Mountains

Estimating abundance of wild animal populations is crucial for their management and conservation. While spatial capture-recapture models are becoming increasingly common to assess the densities of elusive species, recent studies have indicated potential bias that can be introduced by unaccounted spatial variation of detectability. We used camera-trapping data collected in collaboration with local hunters from a transnational population survey of the Eurasian lynx (Lynx lynx) in Slovenia and Croatia, to provide the first density estimate for the threatened Eurasian lynx population in the Northern Dinaric Mountains. Population density was 0.83 (95% CI: 0.60–1.16) lynx/100 km2, which is comparable to other reintroduced Eurasian lynx populations in Europe. Furthermore, we showed that baseline detection rate was influenced by the type of site used, as well as by sex of the individual and local behavioural response. Scent-marking sites had on average a 1.6- and 2.5-times higher baseline detection rate compared to roads and other locations, respectively. Scent-marking behaviour is common for several mammals, and selecting sites that attracts the targeted species is used to increase detection rates, especially for rare and cryptic species. But we show that the use of different location types for camera trapping can bias density estimates if not homogenously distributed across the surveyed area. This highlights the importance of incorporating not only individual characteristics (e.g., sex), but also information on the type of site used in camera trapping surveys into estimates of population densities.

Cheetah communication at scent-marking sites can be inhibited or delayed by predators

Scent-marking is a way for individuals to indirectly communicate; however, the information is not exclusive to a single species and can be informative to a whole community. Prey or competitively inferior species can use scent-marks from predators/dominant species to avoid interactions. Cheetahs are a subordinate member of the large carnivore guild in Africa, yet olfactory communication in this guild has yet to be explored. We explore whether intraguild or intraspecific communication is occurring at cheetah scent-marking sites as well as whether dominant predator avoidance by cheetah occurs in response to predator presence or predator scent-marking. We recorded cheetah behaviour with video recording camera traps at cheetah scent-marking sites where a ‘landscape of fear’ was provided through natural predator presence or manipulated cues of predator presence. We found that cheetah took longer to return to scent-marking sites when a lion or a leopard was the previous species to visit the site. Moreover, cheetah increased the amount of time that they spent sniffing at scent-marking sites when another predator, as opposed to a cheetah, was the previous visitor. Finally, we noted that females never visited a scent-marking site after a predator was present nor when a predators’ scent-mark was present. Our results demonstrate that cheetahs use scent-marking sites for intraspecific communication, but also obtain intraguild information at these sites. Dominant predators can inhibit or at least delay important intraspecific communication around estrous events that occurs between cheetah at scent-marking sites, a novel form of interference competition. Competition occurs between species, and dominant species deprive subordinate species from key resources. Individuals are able to avoid the cost of direct interactions with competitors by using cues (both direct and indirect) such as scents to assess such risks. Using video recording cameras at cheetah scent-marking sites, we provide novel insight into how dominant predator species shape cheetah behaviour through the use of avoidance by cheetah to the presence of dominant predators. Scent-marking sites are important to cheetah communication around reproduction opportunities and territory maintenance; however, dominant predator species’ cues blocked female reproductive signalling at the sites and delay male visitation. This serves as a novel form of interference competition for cheetah, but we suggest that cheetahs maintain communication through the use of multiple sites.

Non-invasive hair sampling of Neotropical otters

Abstract: Sampling wild animal populations using non-invasive techniques is advised when dealing with threatened species. Hair samples provide ecological information like species and individual identification. However, hair trapping is scarcely used in otters, due to their aquatic habits. Most studies are with captive individuals, so there is the need to test non-invasive hair trapping methods in otters in the wild. The aim of this study was to develop a simple and cost-effective method to collect hair from otter species in a non-invasive way. The study was carried out in the Paranapanema River, São Paulo State, Brazil, with the Neotropical otter (Lontra longicaudis Olfers, 1818), a protected species. Hair traps (wooden sticks and tree roots with adhesive tape or wax bands) were set during six nights on river banks, otter trails and scent-marking sites. Traps were baited with otter fresh spraints from other river locations. From the 23 traps, 10 (43.7%) were successful in collecting otter hairs, mostly guard-hair. The sticks were much more efficient than the roots at capturing otter hair (70.6.% vs. 0%) as well as adhesive tape when compared to wax (71.4% vs. 0%). Method simplicity and efficiency suggest that it can be a cost-effective way for collecting otter hairs without the need for capturing individuals. This method can be used for: assessment of local otter distribution; collecting otter hair samples for sex and individual identification (by molecular analysis), trophic ecology (by isotopic analyses), ecotoxicology (by contamination analysis) or behaviour ecology (by hormonal and stress levels analysis). More trapping campaigns should be implemented to further test the method's efficiency.

Where to leave a message? The selection and adaptive significance of scent-marking sites for Eurasian lynx

Scent marking is an important aspect of social organization and intraspecific communication for many mammals, including solitary felids. By selecting specific micro-locations for scent marking, an individual may increase its success in defending its territory and finding mates. Few studies, however, have reported the selection of scent-marking objects and sites by wild felids. To improve our understanding of this behavior and its adaptive significance, we developed and tested a set of mutually non-exclusive hypotheses explaining selection of scent-marking objects by Eurasian lynx (Lynx lynx). We used snow tracking to locate and determine the characteristics of objects lynx used and selected for urine spraying. Lynx did not mark objects according to their availability but selected juvenile conifers and often marked the surface that was sheltered from the elements (“persistence hypothesis”). Lynx also selected for objects similar in size to lynx and objects located on straight road sections and avoided the most frequently available object types. This selection may have both promoted detectability of the messages by the conspecifics (“detection hypothesis”) and reduced energy expenditure of marking (“accessibility hypothesis”). Our study also indicated trade-offs faced by lynx, as the preferred marking objects were often not readily available. Therefore, suboptimal marking objects were sometimes used, most likely in order to maintain the high scent-marking frequency needed throughout their territory. We suggest that Eurasian lynx, and possibly other solitary felids, developed scent-marking behaviors that increase effectiveness and efficiency of their communication. Scent marking is a form of communication that serves several purposes and allows the signals of the sender to reach a receiver indirectly. Persistence and detectability of these signals can have high adaptive value for solitary felids since the signals are essential for advertising territories for competitors and mates. Although both of these uses may depend on the micro-location where scent is deposited, the majority of studies have focused only on the marking sites used by felids and not on their availability or selection. By snow tracking Eurasian lynx, we showed that scent-marking sites most often used are not necessarily the same as the sites selected. We also provide insights into possible adaptive features of felid scent-marking and the possible mechanisms behind the selection of marking objects which likely serve to increase the effectiveness and efficiency of scent marking.

Evaluating the responses of a territorial solitary carnivore to potential mates and competitors.

Successful communication is critical to the fitness of individuals and maintenance of populations, but less is known regarding the social contexts and reactions to scent marking by other individuals in solitary carnivores, including pumas. We evaluated the responses of resident male pumas to visitation and scent marking by potential competitors (other male pumas) and potential mates (female pumas) by capturing and marking 46 pumas (Puma concolor), and documenting scent marking behaviours using motion-triggered video cameras. By comparing resident male puma visitation rates and communication behaviours in response to either male or female visitors, we found that their visitation and communication behaviours were best explained by the combination of visitation by both competitors and potential mates. Resident males returned to scent marking sites more quickly and increased their rate of flehmen response after visitation by a females, while they increased their rate of visitation and duration of visits in response to other males. Male pumas also visited less frequently in summer and autumn when female visitation rates were lower, but males created nearly twice as many scrapes during these visits. This study suggests that advertising for mates when scent marking may sometimes overshadow the importance of deterring competitors and claiming territory.

Ecology of African Civet (<i>Civettictis civetta</i>) in Arba Minch Forest, Arba Minch, Ethiopia

The population density, diet and scent-marking of African civets ( Civettictis civetta ) were assessed at Arba Minch Forest within Nechi Sar National Park in Arba Minch, Ethiopia. The Civet population was estimated over a 5-months period to be 0. 27/ha, of which 0.16 were adults and 0.11 young. Civet diet was analyzed by examining 578 scats during the same period to determine preference of adult Civets to plant material over animal material and vice versa. This viverrid can be termed a generalist omnivore as per these findings. Civets were found to use plants, metallic objects and poles to mark scent. Out of the 92 scent marking sites observed, a vast majority were within 100 m radius of civetries or latrine sites. In the wild, the amount of civet – the perineal gland secretion collected from each marked site varied from 0.0047 g to 0.98 g, but in captivity 0.034 g to 2.0 g was collected. Much as Ethiopia is the world’s largest supplier of civet musk to perfumery industry in Europe, its Civet farming practices needs to be regulated for acceptable welfare standards. Keywords : African Civet Population Omnivorous generalists Scat analysis Scent marking

Hair snaring and molecular genetic identification for reconstructing the spatial structure of Eurasian lynx populations

Non-invasive genetic sampling (NGS) is being increasingly applied in wildlife monitoring and population genetic research. This study was designed to evaluate the use of NGS for reconstructing the spatial structure of populations of large felids. We developed a procedure for reliably genotyping individuals of Eurasian lynx (Lynx lynx) from samples obtained through a hair-trapping scheme based on a network of lynx scent-marking sites. The spatial locations of the identified genotypes were matched with the home ranges distribution of radio-tracked individuals, thus cross-checking the accuracy of the two methods. We analyzed DNA extracted from 170 hair samples and 11 blood samples from live-trapped lynx collected in 2004–2009 in the Białowieża Primeval Forest, Poland. We obtained PCR products in 96 (67%) hair samples; 82 (85%) of them were reliably genotyped at 12 autosomal microsatellite loci following a multiple-tubes protocol and stringent quality-controls of the data set. The sample included 29 distinct genotypes; 18 were found only in hair samples, five were determined only in live-trapped animals, and six in both hair and blood samples. Based on linkage disequilibrium we estimated an effective population size Ne=20.3 (90% CI=15–28). The total population size estimated with Capwire was Nc=32 (95% CI=25–37) in close agreement with the observed number of genotypes. The genotypes obtained from hair samples were re-sampled on average 3.9 times and 50% of them were recorded for more than one year. The spatial distribution of six hair-genotypes was consistent with their home ranges obtained by radio-tracking in the same period. The distribution ranges of hair-trapped genotypes overlapped on average in 86.4% (mode 100%) with home ranges of the corresponding individuals. Hair-trapping and molecular identification is a reliable method for reconstructing the spatial organization of lynx population. It is likely to be also efficiently used in other rare and endangered species of felids in combination with data from other monitoring techniques, such as radio- and snow-tracking and photo-trapping.

Giant panda scent-marking strategies in the wild: role of season, sex and marking surface

Scent marking entails significant energetic and opportunity costs that demand efficiency. Signal detection theory offers a theoretical framework that generates testable hypotheses regarding where animals should place scent signals in the environment in a way that maximizes their probability of detection by target receivers while minimizing costs of production and distribution. Solitary and reliant on chemical communication, the giant panda, Ailuropoda melanoleuca, offers an interesting model to test these ideas. We studied scent-marking patterns in wild giant pandas in the Foping Nature Reserve by surveying areas containing a high density of scent posts. Pandas did not deploy scent marks randomly in this environment, but targeted trees with specific characteristics that promoted signal persistence, range and/or likelihood of detection. Variables affecting selection of scent-marking sites included bark roughnesss, presence of moss on the tree trunk, tree diameter and distance to the trail. That pandas should be efficient with their use of chemosignals comes as no surprise, as mounting evidence is suggesting that many aspects of giant panda life history are constrained by their energetically poor diet. We also found seasonal and sex differences in marking patterns, indicating a role for scent marking in reproduction and competition. Males scent-marked throughout the year, whereas females scent-marked predominantly during the mating season, suggesting functional differences in scent marking between the sexes.

Socio-seasonal changes in scent-marking habits in the carnivorous marsupial Dasyurus maculatus at communal latrines

Scat DNA analyses and monthly monitoring were used to elucidate patterns of latrine use in a free-ranging population of a rare Australian marsupial carnivore, the spotted-tailed quoll (Dasyurus maculatus) Kerr. In all, 132 latrines were identified at large complex outcrops and on bedrock in drainage lines, creeks and rivers at a single woodland site in south-eastern mainland Australia. Annual cyclic variation in scat deposition was found over the two years that latrines were monitored. Peaks in scat deposition on latrines coincided with seasonal social behaviours and differed between sites on outcrops and sites along drainage lines. A marked increase in scat deposition on latrines in drainage lines was recorded during the mating season and at outcrop latrines when females were nursing young. Genetic analyses of scats collected over one breeding season revealed that multiple individuals of both sexes defaecated at latrines. The communal use of latrines during the mating season along with the seasonal patterns of scat deposition demonstrates that latrines are important scent-marking sites that facilitate social communication among individuals of this solitary-living species. The collective evidence indicates that latrines play a major role in aiding reproduction and interindividual spacing.

Field-based evaluation of scat DNA methods to estimate population abundance of the spotted-tailed quoll (Dasyurus maculatus), a rare Australian marsupial

Context. DNA extracted non-invasively from remotely collected scat samples has been used successfully to enumerate populations of a few endangered mammal species. However, scat DNA surveys relying on scent-marking behaviours need to identify if age- or sex-specific variations or seasonal changes in scat scent-marking patterns affect population estimates. Furthermore, owing to the low quantity and quality of scat DNA, a thorough assessment of the technique is needed when it is applied to different species to ensure that individual identification is reliable. Aims. In the current study, microsatellite genetic profiles derived from 208 remotely collected scats of the spotted-tailed quoll (Dasyurus maculatus), a rare Australian marsupial carnivore, were compared with DNA profiles from tissue of 22 live-trapped individuals from the same study area to critically assess the reliability of the non-invasive method to estimate population abundance. Methods. Scat samples were collected at scent-marking sites over 4 consecutive months (April–July 2005), 7 weeks of which overlapped with the trapping program to allow direct comparisons of population estimates. Key results. Combining a multiple-tubes approach with error checking analyses provided reliable genetic tags and resulted in the detection of the majority of the live-trapped population (18 of 22 individuals). Ten additional individuals not known from trapping were also observed from scat DNA. A longer-term sampling regime was required for scats than for trapping to allow direct detection of a large proportion of the population and to provide a comparable population estimate. Critically, the 4-month scat collection period highlighted the importance of performing scat surveys during the mating season when scat scent marking is more frequent, and to avoid sex and age biases in scat marking patterns. Implications. Non-invasive scat DNA sampling methods that rely on scent-marking behaviours need to consider the duration of the sampling period and temporal differences in behaviours by the sexes and age groups to ensure that meaningful population estimates are achieved.

Scent-marking and territorial behaviour of Ethiopian wolves Canis simensis

Scent-marking behaviour and inter-pack aggression were studied in wild Ethiopian wolf, Canis simensis, packs. Raised-leg urinations, followed by ground scratching, were the most frequently deposited scent-mark. Scent-marking rates were highest along or near territory boundaries, where distances between scent-marking sites were reduced and the proportion of multiple marks was increased, relative to other areas. Marking rates increased with wolf numbers during patrols but not during other activities. Although all adult members of a pack contributed to scent-marking, the dominant pair marked most frequently. Subadult males scent-marked occasionally but subadult females never did. Wolves vigorously over-marked neighbours' scent-marks. Most direct encounters between neighbouring wolves at territory borders were aggressive and involved repeated chases, and the larger group was most likely to win. Resident wolves were more tolerant of opposite-sex than same-sex neighbours. Resident wolves therefore signalled pack composition and status at home range borders by olfactory and auditory cues and by aggressive contests. Such signalling may reduce the occurrence of potentially costly inter-pack aggressive encounters at territory borders and provide information on reproductive status.

Selection of scent‐marking sites by klipspringers ( Oreotragus oreotragus )

Klipspringers deposit scent marks in the form of secretion from the preorbital glands on branches of low trees and shrubs within their territories. Local environmental factors which affect choice of scent-marking sites in a population of wild klipspringers in Zimbabwe are described. Scent marks were typically placed within a narrow vertical range at the end of upward-pointing twigs. Twigs were more likely to be selected if they were located above bare rock, particularly if the ground was raised above the immediately surrounding area or was close to a significant break in slope. A substantial proportion of sites were placed on dead wood. Marking sites may remain in use for a number of years, with turnover rates calculated at between 1 and 2% per annum. The species of tree on which marks were placed were recorded and compared with overall abundance in the habitat. Palatable tree species were found to be selected preferentially when compared to unpalatable ones. Several explanations for this are compared. It is concluded that, simply through preferential selection of certain local characteristics, klipspringers may enhance the visibility and predictability of their scent marks.

Scent marking by male dwarf hamsters ( Phodopus sungorus campbelli) in response to conspecific odors

Male hamsters (Phodopus sungorus campbelli) scent marked at greater frequencies in the presence of conspecific odor, either male or female, than in clean areas. Marking rates were not different between male and female odor conditions. In contrast, the pattern of investigation in response to conspecific odor did differ between the male and the female odor conditions. When male odors were used as stimuli, investigative sniffing increased at the scent marking sites but when female odors were used as stimuli investigative sniffing increased throughout the arena. Thus, male dwarf hamsters direct their scent marks at both male and female conspecifics, discriminate between male and female odor, and investigate in a different manner areas scent marked by males and females.